4,4'-Dihydroxybiphenyl → Phthalonitrile

Temperature

100 °C

To a 100 ml, 3-necked flask equipped with a thermometer and a Dean-Stark trap was added 12.01 gm (55.1 mmol) of 4,4'-difluorobenzophenone, 20.11 gm (108.1 mmol) of 4,4'-dihydroxybiphenyl, and 70 ml of dimethylacetamide (DMAC). After flushing the mixture for 20 minutes with dry nitrogen, 21.2 gm (153.4 mmol) of pulverized anhydrous potassium carbonate was added with stirring. The Dean-Stark trap was filled with toluene. Five milliliter of toluene was also added to the reaction mixture. The mixture was then heated at 100° C. for 1 hour and at reflux (140° C.) for 12 hours total. During this time, the water formed as a by-product was removed by azeotropic distillation. After refluxing, the toluene was removed by distillation. When the temperature of the reaction mixture had reached 165° C., it was assumed that the toluene had been removed. The reaction temperature was then reduced to 90° C. whereupon 19.0 gm (109.8 mmol) of 4-nitrophthalonitrile was added. The reaction mixture turned purple. The reaction content was then stirred at 95°-100° C. for 16 hours (overnight). The reaction was monitored by FTIR spectroscopy and showed the complete disappearance of the absorptions attributed to the nitro group. The room temperature mixture was poured into 50% aqueous ethanol with stirring. The solid precipitate was collected by suction filtration, washed exhaustively with water, washed with ethanol, and dried to afford 39.8 gm of oligomeric phthalonitrile monomer. A DSC thermogram showed an endothermic transition between 260°-280° C.

1. customTo a 100 ml, 3-necked flask equipped with a thermometer
2. additionwas added
3. temperatureat reflux (140° C.) for 12 hours total
4. customwas removed by azeotropic distillation
5. temperatureAfter refluxing
6. customthe toluene was removed by distillation
7. customhad reached 165° C.
8. customhad been removed
9. additionwas added
10. stirringThe reaction content was then stirred at 95°-100° C. for 16 hours (overnight)
11. stirringwith stirring
12. filtrationThe solid precipitate was collected by suction filtration
13. washwashed exhaustively with water
14. washwashed with ethanol
15. customdried

ORD record

ord-94ff7ada361648578bd8f57c3a1f6fbf

Source dataset

uspto-grants-1995_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05464926